ERBB2 and breast cancer: The ExteNET trial demonstrated that neratinib-extended adjuvant therapy reduced relapse and improved invasive disease-free survival (iDFS, 90.2% vs. 87.7%) in women with HER2-positive breast cancer and after trastuzumab adjuvant therapy; thus, the FDA approved neratinib for extended adjuvant therapy in early HER2-positive breast cancer [63].